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Linux KernelOperating system · Linux

CVE-2018-1087

HIGH · 7.8 CVSS v3.0 Published 2018-05-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
kernel KVM before versions kernel 4.16, kernel 4.16-rc7, kernel 4.17-rc1, kernel 4.17-rc2 and kernel 4.17-rc3 is vulnerable to a flaw in the way the Linux kernel's KVM hypervisor handled exceptions delivered after a stack switch operation via Mov SS or Pop SS instructions. During the stack switch operation, the processor did not deliver interrupts and exceptions, rather they are delivered once the first instruction after the stack switch is executed. An unprivileged KVM guest user could use this flaw to crash the guest or, potentially, escalate their privileges in the guest.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A flaw in KVM's handling of exceptions delivered after stack switch operations (Mov SS or Pop SS instructions) allows unprivileged KVM guest users to crash the guest or potentially escalate privileges within the guest. The processor delays exception delivery until after the first instruction executes post-stack switch, creating a race condition that can be exploited.

MitigationUpgrade the host kernel to version 4.16 or later (or apply relevant backported patches) to fix the KVM exception handling vulnerability. This is a hypervisor-side fix that resolves guest privilege escalation risk.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:= 4.16= 4.17
Ubuntu LinuxOperating system
Affected:= 14.04= 16.04= 17.10
Debian LinuxOperating system
Affected:= 8.0= 9.0
Enterprise LinuxOperating system
Affected:= 7.0
Enterprise Linux DesktopOperating system
Affected:= 7.0
Enterprise Linux ServerOperating system
Affected:= 7.0
Enterprise Linux Server AusOperating system
Affected:= 7.2= 7.3= 7.4
Enterprise Linux Server EusOperating system
Affected:= 7.3= 7.4= 7.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify host kernel version
    Run `uname -r` or check `/proc/version` to determine the running kernel version on the KVM host
    Affected if The kernel version is 4.16.x or 4.17.x (any subversion within these major.minor releases)
  2. Verify KVM hypervisor is in use
    Check for KVM kernel modules with `lsmod | grep kvm` or check virtualization capability with `cat /proc/cpuinfo | grep vmx` (Intel) or `svm` (AMD)
    Affected if KVM modules (kvm, kvm_intel, or kvm_amd) are loaded and the CPU supports hardware virtualization
  3. Confirm host is the hypervisor
    Check if the system is running as a virtualization host: `systemctl status libvirtd` or `virsh list` to see if guests are defined
    Affected if The system is configured as a KVM hypervisor with virtual machines running or defined
  4. Check for distribution-specific kernel version
    For Ubuntu: `dpkg -l | grep linux-image`. For Debian: `dpkg -l | grep linux-image`. For RHEL: `rpm -qa | grep kernel`
    Affected if The installed kernel package version corresponds to affected Ubuntu (14.04, 16.04, 17.10), Debian (8.x, 9.x), or RHEL 7.x releases

You are affected if your KVM hypervisor host is running a kernel version in the 4.16.x or 4.17.x series, or running an affected distribution kernel (Ubuntu 14.04/16.04/17.10, Debian 8.x/9.x, RHEL 7.x) with KVM virtualization enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade the host kernel to version 4.16 or later (or apply relevant backported patches) to fix the KVM exception handling vulnerability. This is a hypervisor-side fix that resolves guest privilege escalation risk.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-1087 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data